Background: The aim of this study is to analyze interferon-gamma release assay (IGRA) data of foreign-born individuals in Japan derived from tuberculosis (TB) contact investigations.
Methods: A contact with a TB patient was considered to have occurred when an individual had contact with a TB patient for more than 8 h indoors. This is a retrospective cohort study, and all the TB contacts tested with IGRA during the contact investigations conducted by the Shinjuku city Health Office from 2015 through 2017 were enrolled.